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Why would a battery charger mess up FM reception?

Lucky Pierre

Lucky Pierre

AK Subscriber
Subscriber
Greetings,

My garage system is a Sansui 880 with original CSW Ensemble satellite system. The receiver is plugged into the same circuit as two Milwaukee chargers, one an M12, one a combo M12/M18. If there is a battery plugged into the M12/M18 charger, the FM reception goes all to hell. If there is no battery in the charger, FM is great.

Interestingly, if I plug a battery into the M12 solo charger, it does not affect FM reception.

What would cause this?

Peter
 
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Those chargers supply pulsed DC to the battery, so there's a high amount of fast switch current which creates RF interference. That and the switch mode power supply in these things...

I have a battery tender to keep my old cars charged up, and it does the same thing when connected to the car battery.
 
Interesting! Thank you.

If I increase the distance between the charger and the receiver, should it help? Also, why would it only happen with one charger and not the other?
 
SHould help, yes. Perhaps try one of those snap-on ferrites. Perhaps the one charger has a different design, or there's something failed/failing in it. A good SMPS design will have filtering at the AC input; perhaps one of the capacitors has failed. I presume it's one of those chargers you insert the battery into, and not one that has a cord that plugs into the battery somewhere? If the latter, shortening that cord might help also, or using a ferrite on it.
 
Thanks again.

It is one of the chargers that you plug the battery into. It's probably more than a few years old and has seen better days. A buddy gave it to me.

I'll move it further away. And probably not charge batteries while I am listening to the radio!
 
I had the exact same issue with my Milwauke M12/M18 charger. I had put the charger on a counter beneath my old Realistic under-cabinet radio, which actually has very good FM reception in the basement. As soon as I put a battery in the charger, reception is terrible.
 
w3jn said:
Those chargers supply pulsed DC to the battery, so there's a high amount of fast switch current which creates RF interference. That and the switch mode power supply in these things...

I have a battery tender to keep my old cars charged up, and it does the same thing when connected to the car battery.
Click to expand...

Yes, this post's advice is dead on. Pulsed DC and the switch mode power supply messes with radio reception severely.
 
I have charged Dewalt batteries and ran a battery tender off the same outlet as my receiver and had no FM problems.
 
Not a battery charger but...I got some of those LED lights that screwed into a conventional socket but with four "petals" of LED's. I put them in my garage to replace the original florescent fixtures.
They were amazingly bright.
But they would blare so much RF noise they would swamp my garage receiver and effect my car until I got to the end of the driveway!
Yes..they were from China.
 
Decades back I had purchased a small Guest brand 12v battery maintainer for use for my 7kw portable genset`s starting battery that that genset was a backup to the main automatic whole house genset and discovered that it interfered with SW reception (I quit listening to any FM radio yrs. before) with a annoying strong ticking pulse noise, even though the room with my well grounded receivers was at the other end of my house.
And I had 90 + ft. long and ~36 ft. elevated high sky wires strung out away from the house.

So I gave it to my friend for use on his jet ski, and purchased another brand (Shaffer, I think), and that cured my SW listening interference.
 
Lucky Pierre said:
Greetings,

My garage system is a Sansui 880 with original CSW Ensemble satellite system. The receiver is plugged into the same circuit as two Milwaukee chargers, one an M12, one a combo M12/M18. If there is a battery plugged into the M12/M18 charger, the FM reception goes all to hell. If there is no battery in the charger, FM is great.

Interestingly, if I plug a battery into the M12 solo charger, it does not affect FM reception.

What would cause this?

Peter
Click to expand...

I too run the Milwaukee M12 line and have experienced this, I listen to a lot of radio, and when I have the standard M12 charger plugged it I loose reception. I always assumed it was due to the poor electrical wiring at our apartment, but sounds like it’s a Milwaukee thing.
 
Lucky Pierre said:
Thanks again.

It is one of the chargers that you plug the battery into. It's probably more than a few years old and has seen better days. A buddy gave it to me.

I'll move it further away. And probably not charge batteries while I am listening to the radio!
Click to expand...

Or just buy the M12 Radio, it has a built in charger
 
Lucky Pierre said:
Hmmmmm, M12 radio or Sansui...;)
Click to expand...

Yea I know the feeling, I currently have an older Sony radio playing, it’s from the 60s. I have a bunch of various tuners and radios I like to use. I like to listen to the radio while I clean or work on various projects. When I do have a Milwaukee charger going I do notice i loose reception, none of the other chargers I use for other tools will have this effect, it’s only the Milwaukee ones. Kinda odd actually.
 
RVT1K said:
Not a battery charger but...I got some of those LED lights that screwed into a conventional socket but with four "petals" of LED's. I put them in my garage to replace the original florescent fixtures.
They were amazingly bright.
But they would blare so much RF noise they would swamp my garage receiver and effect my car until I got to the end of the driveway!
Yes..they were from China.
Click to expand...

I have the exact same problem in my garage, led's causing interference with my receiver.
 
amazing the sheer quantity of badly designed things in the world, but I very much doubt that a lot of this stuff has any actual testing or certification done to ensure its not just a noise-producing mess.
 
gadget73 said:
amazing the sheer quantity of badly designed things in the world, but I very much doubt that a lot of this stuff has any actual testing or certification done to ensure its not just a noise-producing mess.
Click to expand...

I'm willing to bet that the units I had were not compliant with any FCC regs and it is entirely possible they were counterfeits of units that were.
 
Lucky Pierre said:
Greetings,

My garage system is a Sansui 880 with original CSW Ensemble satellite system. The receiver is plugged into the same circuit as two Milwaukee chargers, one an M12, one a combo M12/M18. If there is a battery plugged into the M12/M18 charger, the FM reception goes all to hell. If there is no battery in the charger, FM is great.

Interestingly, if I plug a battery into the M12 solo charger, it does not affect FM reception.

What would cause this?

Peter
Click to expand...
You know... I seem to remember, in the early 1990s (1993?? I think), my sister had a computer, a 386, she was using. My dad used to listen to talk radio. I don't recall if it was AM or FM, but that computer put horrific static on the radio.. Perhaps this is a similar situation.
 
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